JPS6036606A - Molding method of composite sintered parts - Google Patents

Abstract

PURPOSE:To econimize the amt. of the costly rare element to be used by molding successively the 1st and 2nd layers by stamping to a required density and shape and changing the thickness of the members for the 1st layer and 2nd layer in accordance with a change in the thickness of the axial direction. CONSTITUTION:A die is constituted of an upper punch 3, a die 4, a lower punch 5 and a core 6. The 1st layer powder is packed in the die and the punch 3 is lowered to perform the 1st pressurization thereby preforming the shape of the joint surface between the 1st layer (base part) 1 and the 2nd layer (special alloy layer) 2. The punch 3 is then risen and the 2nd layer powder is packed into the die. The 2nd pressurization is performed by the punch 3 to mold the powder to the required density, shape and size and to change the thickness of the members for the 1st layer 1 and the 2nd layer 2 so as to correspond to the thickness of the axial direction. Such molding is taken out of the die and is sintered to form a composite sintered part. The amt. of the 2nd layer 2 to be used is thus economized and the strength to sliding friction is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to an improvement in the method of forming composite sintered parts used as sliding wear-resistant materials.

(b) Prior art and its problems Automatic - 1 Sintered parts used as engine valve seats and other sliding friction materials are made of expensive special alloys of rare elements due to their required characteristics, and the manufacturing cost of raw materials is low. Since it accounts for a high proportion of costs, the challenge is to reduce costs by reducing it.

As a countermeasure to this, we have developed a composite sintered 1-part 0-part structure that uses special alloys only for the parts with strict required properties, and the rest is made of inexpensive materials.
Development of forming method 0 is desired - 'In the conventional method, the boundary surface is a flat or cylindrical surface as shown in Figure 1, and after sintering, it is machined into the specified shape as shown in Figure 2, so it is special. The thickness of the alloy layer became thin, the base was easily exposed, the special alloy layer had to be made thicker than necessary, and machining was also expensive, and there was a lot of material loss due to machining allowance. . Furthermore, areas with large machining allowances tended to lack sliding friction strength.

(c) Structure of the Invention It is an object of the present invention to eliminate such drawbacks and provide an improved method for forming composite sintered parts.

The embodiment of the present invention shown in FIGS. 3 and 4 will be described below.

The third longitudinal cross-sectional view of the composite sintered part formed according to the present invention is shown in FIG.
As shown in the figure.

The overall thickness changes in the radial direction from the outer diameter part to the inner diameter part, and the thicknesses of the base (first layer) and special alloy layer (second layer) change accordingly.

FIG. 4 shows a method for forming a composite sintered alloy according to the present invention.

'' = In order to fill the first layer powder into a mold consisting of punch 3, die 4, lower punch 5 and core 6, the upper punch is lowered, first pressure is applied, and the first layer is filled with powder. The shape of the joint surface between the layer and the second layer is preformed (FIG. 4b). Further, the upper punch is raised and the second layer powder is filled (FIG. 4C). Next, insert the upper punch into the entire mold and apply a second pressure to form it into the desired density, shape, and dimensions (Fig. 4 d), and take it out from the mold (
Figure 4e). Furthermore, a composite sintered part is obtained by sintering in the same manner as before.

In the molding method of the present invention, the lower punch and the lower punch may be composed of one part, but as in the -shell powder molding method, they may be composed of a plurality of parts. Further, each component may be moved differentially in each process to change the thickness of each layer or to make the density uniform.

B) Effects of the Invention According to the present invention, the amount of expensive rare elements used can be reduced;
The machining time is reduced by about 20%, and the sliding friction strength is stabilized due to the uniform thickness of the special alloy layer.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional molded product, and FIG. 2 is a sectional view of a conventional interest mold.

Claims (2)

[Claims] (1) In a composite sintered part composed of two types of materials that differ in the axial direction, the first layer powder is filled into a mold, and the first pressure is applied using an upper punch and a lower punch having the desired shape. conduct,
Next, the second layer powder is filled, a second pressure is applied by the upper punch and the lower punch, the molding is performed to the desired density and shape, and the first layer and the second layer are A method for forming a composite sintered part, which is characterized by creating an embossed molded product in which the thickness of two layers of members changes. (2) The method for forming a composite sintered part according to claim (1), wherein at least one of the first layer and the second layer is multilayered with different sintered alloys.